funny note: it's a good thing mah bus came without seats, as in Nebraska, you have to have a licensed bus seat remover unscrew those bolts :\ i kid you not.
The obvious solution here would seem to be an angle grinder...that way, no unscrewing needed.
(I think about six of mine actually unscrewed, out of 24 seats with something like 4-8 bolts in each.)
I made my rear lights into brake & turn signals...something to think about. I used car-type sockets & 1156 bulbe...were I to do it over, I'd use the disposable "Truck-Lites" that many semi tractors & trailers have for taillights--cheap, weathertight, available at any truck stop or auto-part store, & nowhere near as many 4-letter words used during the install.